Modelling terrain improvements

ABSTRACT

A terrain model element and method of manufacture which has a latex shaped layer molded in a drying mold and supported by a flexible foamed plastics material. In one instance the foamed plastics is molded directly into the latex layer.

TECHNICAL FIELD

This invention relates to modelling terrain.

BACKGROUND ART

Modellers use terrain units to create the three-dimensional visuallyappealing terrain in combination with models for various purposes suchas, for instance, playing war games or incidental scenery for a modelrailway and the like.

Conventionally this terrain is provided by individual units being placedtogether on a supporting surface so that they fit in an adjacentrelationship to provide a continuity across a selected area.

Several of the problems which are being addressed by this invention willnow be discussed.

A current constructional method uses a polystyrene base with an upperform provided by a resin.

Difficulties relate to this current method insofar that the units are,because of their character, vulnerable to damage including having anypainted surface chipping or even edges of the styrene being broken.

A further problem is that the current materials make up units which arein comparative terms quite heavy. This is of concern where, forinstance, a modeller may be competing in a competition where the terrainmust be carried to the competition location by the modeller. In themaking of terrain modules, it is exceedingly difficult to achieveanswers to a combination of challenges.

Some materials which have been used in the past and to some extant arestill being used by some currently, such as styrene and resin, exhibitvulnerability to being easily broken and damaged, for instance by notproviding a sufficient adhering surface for coatings such as paints orflocks.

Another problem is the physical all up weight that might result from theuse of specific materials. This is of concern when the terrain modelsmight be being used by war garners who may need to transport theirmodules to different locations either within a country or of courseinternationally.

Further, them is great attraction in having the ability to have complexshapes which add to interest in the terrain itself by others buthitherto, there are some limits purely based upon availablemanufacturing techniques which can be provided at an economic level.

Latex has been found to provide a useful upper layer providing a formonto which colouring materials and surface finishes can be applied, butit is a material that has enormous complexities and these complexitieshave hitherto made it either very difficult, or for some impossible, touse as an upper layer material for terrain models.

OBJECT OF THIS INVENTION

It is an object of this invention to reduce at least one or more of theabove problems.

DISCLOSURE OF THE INVENTION

In one form of this invention, there is proposed a terrain model elementwhich includes a base of a foamed plastics malarial having adhered on anupper face a shaped layer providing the modelling terrain shape which iscomprised of latex.

In preference, the base is sheet-like.

In preference, the foamed plastics material is a flexible foam.

In preference, the plastics foam material adheres to the late by reasonof being directly molded into the latex layer.

In preference, the latex layer is molded so as to be within the range ofthickness, at least substantially through the extent of the layer ofbetween 1 millimetre and 10 millimetres.

In preference, the foamed plastics fills or substantially fills theotherwise open cavity shape of an underneath surface of a latex upperlayer.

In preference, the upper modelling layer of latex is formed so that itincludes parts that are adhering to an upper surface of the basematerial and other parts of which are hollow and which therefore have alowermost surface which is above and separate from an uppermost surfaceof the base material.

This accordingly leaves a hollow area which in practice has someadvantage especially since it implicitly keeps the weight of the unitlow and it has been found to still provide an adequate shaping inpractice and to allow a higher degree of flexibility of the shape whichmakes this potentially less vulnerable to impact and therefore wear andother damage.

One of the problems with latex however where this is a material that canbe either sprayed or brushed on to the inside of a mould so that itsshape is formed as a thin layer, is that as the material cures, it isespecially vulnerable to contraction in one direction as compared to anytransverse direction.

It is fairly obvious therefore that this will cause difficulties withterrains in terms of joining units together so that there is acontinuity of the shape.

As the actual unilateral direction of contraction may not always be ableto be accurately predicted, this makes it even worse for predicting theend result, subsequent to casting this material, and especially wherethe purpose of the production is for mass production purposes.

We have discovered that there is an advantage during the application andinitial curing stage by having at least a surface of the mould such thatit will adsorb moisture from the applied latex.

In preference, such absorption can be achieved by using a material suchas Plaster of Paris, which is implicitly porous and in practice absorbsa significant amount of water.

My discovery is that tis technique then of providing a mould of thisabsorbent material assists in reducing differential contraction of thecuring latex material and therefore provides for more reliability inachieving an end shape that will be of consistent size and shapesubsequent to an initial curing and stripping from the mould stage.

A further difficulty in relation to previous modelling units is that theshaping form of resin that will be painted, over time, is found to loseadhesion.

Accordingly, conventional paint which is applied to resin after a periodbecomes chipped and breaks away, so that continual reapplication ofpaint or a reduction in the quality of the terrain results.

A further discovery has been that with latex, most acrylic paints can beapplied and will adhere initially “well” but, surprisingly, over time,thy become even more integrated with the latex so that after asignificant period of time, I have discovered that the latex self can bestretched with e paint and with an appropriate selection of paint, thepaint itself will stretch with the latex without breaking away orwithout showing any separation of the paint layer itself.

This then is of significant advantage in this business.

In preference, the base unit is made from a foamed plastic and, in thiscase, from a urethane foam which I have found can be adhered effectivelyto a latex upper layer.

Our discovery has been that a self-adhesive material can be provided andsheets of polyurethane foam with such a self-adhesive upper surface canbe purchased commercially in this form.

Reference has been made to terrain units and it is intended in thisinvention that the shape of such units shall be such that in plan theywill provide for joining with other units to provide some form ofcontinuous terrain shape.

This will then implicitly presume that the thickness at adjoining oradjacent edges are relatively matched, which is to say that the heightabove a supporting surface level will be the same in respect of suchadjacent units or units that are expected to be adjacent. Various planshapes can be used. For instance, they can be a regular hexagon, asquare, or a triangle, as typical instances.

A typical thickness of the sheet might be twenty millimetres, althoughat least within the form there can be some change of thickness and toillustrate, it might have a step up to forty millimetres or even fiftymillimetres in some case. Again, as a typical illustration, that alsowith the consideration in mind tat if these are to be placed on a commonplanar surface in an adjacent vicinity, the terrain is expected to bematching and therefore the relative height above the supporting surfacewould be normally consistent.

This is not to say that ere should not be tailor-made variations fromthis where a particular effect is to be achieved.

The latex layer itself might be two or three or more millimetres inthickness as a separate sheet having, however, this characteristic thatin parts, it is separated and therefore leaves a void or hollows beneaththe sheet or thin layer of latex as compared to the underneath basematerial.

The actual thickness of the latex sheet itself is not found to beespecially critical as it is formed by brushing or spraying onto areceiving model surface so that such thickness can vary from applicationto application. However, it is conventionally very much thinner than thebase of supporting material.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of this invention it will described withreference to drawings wherein:

FIG. 1 there is a cross section through a unit,

FIG. 2 is a perspective view of a single hexagonal void,

FIG. 3 shows a perspective view of a number of units located as theywould be to provide a continuity of scene;

FIG. 4 is a perspective illustration of a mold for manufacture of anupper latex layer for a second embodiment;

FIG. 5 is a cross-sectional view through the mold in FIG. 4;

FIG. 6 illustrates a first step in the molding of the upper latex layerfor the second embodiment;

FIG. 7 illustrates the removal of excess latex so as to leave a verythin and dried surface coating which forms the upper latex layer;

FIG. 8 illustrates the introduction of foamed plastic which when foamedand polymerised will of itself be flexible and which also will beadhering to the lowermost facial surface of the upper lax layer; and

FIG. 9 illustrates the positioning of a capping on the mold so as toconstrain the extent to which the foaming plastics will extend and willfurther provide a planar base once removed from the completedpolymerised result.

BEST MODE FOR CARRYING OUT THE INVENTION

Shown in the drawings then Is a base unit showing a hexagonal planshape, which is of regular hexagonal shape such that this can fit withadjacent units as shown in FIG. 3, and has a form that will generallymatch both in terms of continuity of shape and height such adjacentunits.

The base 1, is made from polyurethane foam of normal thickness and thereis a latex surface 2 which is adhering across a top of this underneathbase 1.

There are parts within the latex that lies above a base level and leavea void as shown in 3.

In order to get to the shape shown, the latex is purchased as a liquidappropriate for brushing or spraying (it can be either type of material)and this is laid as a thin layer on to the Inside surface of a mouldmade preceding this from Plaster of Paris.

The Plaster of Paris is such that it will be porous and has theadvantage that this ability to absorb the moisture appears to restrictdifferential contraction during the curing of the latex. Once anadequate curing stage has been reached, the latex is stripped from themould and is then applied from a base unit as is shown in 1, which has aplanar upper surface with a self-adhesive coating appropriate to adherethe latex to the upper surface of the base material.

The foam from which the base is made is a flexible polyurethane foamwhich has the significant advantage of being very robust in beinghandled, firstly, because it is flexible and secondly, it can be benteven grossly without causing damage, as contradiction to rigid foam.

The advantage of having the latex layer, as has been previously stated,is that this then will receive acrylic paints (and this applies to mostacrylic paints that we have tried) which thereby adhere and seem toincrease their adhesion over time to the stage where, after a year orso, in our experience, the stretching of the latex will result only Inthe paint surface itself also stretching with the surface withoutbreaking or fracturing away.

Now referring to the second embodiment this is different to the firstinsofar that an upper latex layer is formed which has a foamed plasticsmolded and foamed directly on to the back or lower surface of the upperlatex layer.

The discovery in the first instance has been that such a material is nowcommercially available and further, provides adequate adhesion duringthe molding process to the underneath latex surface.

The relevance of it being flexible is twofold.

A first difficulty with the manufacture of terrains Is to make theminteresting, and this effect is assisted dramatically by havingpotential for undercutting shapes and ally deeply undercutting shapes,for instance shapes that can simulate caves, even deep caves, tunnels oreven the more straightforward shapes such as bus and in many casesbuildings.

It can be well imagined that by being able to provide under it canprovide a designer with many more opportunities for interesting formsand shapes.

Hitherto then, if a traditional rigid foam was used, while it may beable to provide adequate support and to some extent infill intocavities, in a practical sense, it becomes either very difficult or inan economic sense, impossible in the particular market for there to belikewise included undercutting shapes.

However, by using flexible foam, and understanding that latex itselfonce dried is both modestly elastic and also deformable, then such afilled latex shape where the filling is flexible foam, allows for thematerial then to be extracted from what can be quite complex andintrusive mold shapes, which can therefore include features such ascaves, or be built quite high (2 to 3 feet for instance) in places forthe purpose of modelling mountainous terrain or the like.

Further, because the foam plastic itself can be caused to infillsubstantially into perhaps complex shapes and provide these withsubstantial internal support, the whole unit itself then Is strengthenedinternally and what this means Is that you do not need as a separatebase thickness, a thick separate element.

This then provides advantage both in overall cost of materials, all upweight of a module, and for these and other reasons as well, a reductionin the complexity of manufacture.

Looking at the drawings for the second embodiment then, there is a mold5 which is formed from Plaster of Paris so that it has a porous andtherefore water absorbent surface.

There is shown in this mold, at least one undercut portion which will beuseful to indicate a cave in the eventual product, this being shown as6.

Latex is a natural product being the sap of rubber trees and the curingprocess is achieved simply by drying this.

Referring now to FIG. 6, the latex in this Instance is therefore pouredso as to be slightly in excess of that needed for the eventual layerthickness but so that there is a relatively uniform coating over all ofthe respective surfaces of the mold which attach simply by adhesion inits wet stat and the curing process is achieved by this drying effect.

In practice, this effect can be assisted by the addition of a firstapplication of a dehydrating material such as methylated spirits, whichby reason of its alcohol content will provide such a dehydrating effect.

The mold containing the excess liquid latex Is caused to be distributedso as to more or less keep this adhering surface relatively uniformlythick and as a matter of time and temperature, such a step is continuedfor a sufficient period for the selected thickness of the latex as thefinished upper latex layer. This selected thickness may be varieddepending on the circumstances but may be at least within a range offrom 1 mm to 10 mm thickness.

One of the problems that had previously been explained as existing isthe characteristic of latex to develop internal directional tensionswhich cause the material to curl and change shape and especially wherethe tension provided is in unpredictable or random directions.

A first solution to this is to keep the actual thickness of the latexupper layer as thin as can be reasonably achieved while stillmaintaining an adequate thickness for strength purposes and this isachieved by restricting the time during which the latex with excessmaterial in the mold is allowed to remain in the mold with such excess.

Referring now to FIG. 7, once a reasonable period, perhaps five minutes,has passed which is a period which is based upon a judgement based uponexperience in the circumstances, then the excess latex that has not yetbeen dried, is poured off and the then remaining thin film of latex 7 Inthe die surface is allowed to further dry expect that relatively soonafter, a catalysed foaming mixture 10 of plastics monomer together witha foaming agent is inserted into the area shown at 8 and a capping 9 inthis case which is a Perspex sheet with plurality of holes passing therethrough to allow for release of air, otherwise it might be trappedwithin the expanding mold foam areas is put in position. The capping 9is in this case, screwed to a wooden frame formed into the mold 5.

Plastics materials which is also flexible and the degree of flexibilityis again based upon a judgement of the degree of flexibility appropriatefor removal of the thus formed material from overhangs, is then allowedto set which is achieved by simply allowing the material a sufficienttime for adequate polymerisation to take place so that the shape willthen be relatively established.

The resulting complex product with an upper latex surface and innerflexible foam then has surface coding supplied to the upper surface ofthe latex layer for instance acrylic paints or flock which is applied byadding such flock after a surface coding such as acrylic paint or otheradhering material is applied as a base.

As will be seen now with this second embodiment, as with the first,these both then provide for a very excellent means by which the terrainmodelling process can be significantly improved, and in practice it hasshown itself to provide tremendous advantage both in the degree to whichthe various possible shapes including undercut shapes can now be evenmore faithfully and realistically reproduced while at the same time, thecost of production can be very economic and the all up weight of theresulting units can be kept very low indeed which is where war-gamersmight want to transport their terrains to various locations.

The invention applies to both units manufactured in accordance with thedescription, the method of construction and to assemblies using suchunits in combination.

It also applies to the units where constructed in a regular plan shape,including hexagonal, square and triangular.

It is considered that the modelled terrain segments and the methods ofproduction thereof, such as those described herein, would prove to be ofconsiderable benefit to those who use modelled terrain for such purposesas war gaming, model railways, architectural models, dioramas, museumdisplays and so on.

1-23. (canceled)
 24. A terrain model element which includes a base of afoamed plastics material having adhered on an upper face thereof ashaped layer providing the modelling terrain shape, which is comprisedsubstantially of latex.
 25. The terrain model element as in claim 24wherein the base is sheet-like.
 26. The terrain model element as inclaim 24, further characterised in that the foamed plastics material isa flexible foam.
 27. The terrain model element as in claim 24, furthercharacterised in that the foamed plastics material adheres to the latexby reason of being directly molded onto the latex layer.
 28. The terrainmodel element as in claim 24, further characterised in that the shapedlayer is molded so as to be within a range of thickness, at leastsubstantially through the extent of the layer, of between 1 millimetreand 10 millimetres.
 29. The terrain model element as in claim 27,further characterised in that the foamed plastics material fills orsubstantially fills an otherwise open cavity shape of an underneathsurface of the shaped latex layer.
 30. The terrain model element as inclaim 25, further characterised in that the shaped layer of latex isformed so that it includes parts that are adhering to an upper surfaceof the base material, and other parts which are hollow and whichtherefore have a lowermost surface which is above and separate from anuppermost surface of the base material.
 31. The terrain model element asin claim 24, further characterised in that the latex layer is formed andcured in a mold that will absorb moisture from the latex appliedthereto.
 32. The terrain model element as in claim 31, furthercharacterised in that the mold is formed from Plaster of Paris, as it isimplicitly porous and can absorb a significant amount of water.
 33. Theterrain model element as in claim 24, further characterised in thatthere is a coating on an upper surface of the shaped layer which is anacrylic based paint.
 34. The terrain model element as in claim 24,further characterised in that the base unit is made from a urethanebased foamed.
 35. A combination of terrain model elements including atleast two terrain model elements, which are located one alongsideanother to provide a continuous terrain appearance, and where each ofthe elements is as described in claim
 24. 36. The terrain model elementas in claim 24, further characterised in that the upper latex layer hasthe plastics material molded and foamed directly on to the back or lowersurface of the shaped layer.
 37. The terrain model element as in claim36 further characterised in that the foamed plastics material whenfoamed and cured, remains flexible.
 38. The terrain model element as inclaim 24, further characterised in that the shaped layer includes anundercut shape.
 39. The terrain model element as in claim 24, furthercharacterised in that the element has a plan that is hexagonal in shape.40. A method of manufacture of a terrain model element which includesthe steps of forming a mold for an upper shaped layer of the element,which is adapted to effect a moisture reducing effect, applying liquidlatex to the mold and leaving this so that at least some of the latexclosest to the mold surface is caused to dry and effect thereby a thinlayer of solidified latex; pouring out from the mold any excess liquidlatex, then adhering a backing to the shaped upper layer of latex whichis of a foamed flexible plastics material.
 41. The method of manufactureof a terrain model element as in claim 40 further including the stepseffecting the backing by directly inserting catalyzed and foamingflexible plastic monomer into a cavity of the shaped layer.
 42. Themethod of manufacture of a terrain model element as in the claim 24,further characterised in that the mold is coated with a dehydratingliquid before the liquid latex is applied.
 43. The method of manufactureof a terrain model element as in claim 42 further characterised in thatthe dehydrating liquid includes alcohol.
 44. The method of manufactureof a terrain model element as in claim 24, further characterised in thatthe liquid latex is applied and left in the mold until a solidifiedlayer of between 1 mm and 10 mm in thickness is formed, after which theliquid remaining is drained off.
 45. A terrain model element producedusing the method of claim 40.